Rendering a cellulose-polyester fabric flame retardant

ABSTRACT

A fabric composed of about 50 percent cotton and 50 percent polyester is rendered durably flame retardant by first treating it with an aqueous liquor containing a dye carrier for polyester and an emulsified aqueous liquor of tris 2, 3, dibromopropylphosphate. After thermosoling the treated fabric it is passed through an aqueous solution containing precondensate of tetrakis (hydroxymethyl) phosphonium chloride. The thus treated fabric is dried to reduce its moisture content to about 10 percent by weight of the original dry weight of the fabric and placed in an atmosphere of ammonia gas for 10 minutes and subsequently oxidized, soaped and dried.

United States Patent [191 Chapin Nov. 25, 1975 [75] Inventor: Jay C. Chapin, Marblehead, Mass.

[73] Assignee: Ventron Corporation, Beverly,

Mass.

[22] Filed: July 6, 1973 [21] Appl. N0.: 377,028

[52] US. Cl. 427/402; 8/116 P; 8/115.7;

427/337; 428/277; 428/121 [51] Int. Cl. C09K 3/28 [58] Field of Search 8/116 P, 17, 18; 117/136 [56] References Cited UNITED STATES PATENTS 3,549,309 12/1970 Ring 8/116 P 3,645,936 2/1972 Gardner 8/116 P FOREIGN PATENTS OR APPLICATIONS 981,098 12/1961 United Kingdom 8/84 Primary ExaminerDonald Levy Attorney, Agent, or FirmJ. Harold Boss [57] ABSTRACT A fabric composed of about 50 percent cotton and 50 percent polyester is rendered durably flame retardant by first treating it with an aqueous liquor containing a dye carrier for polyester and an emulsified aqueous liquor of tris 2, 3, dibromopropylphosphate. After thermosoling the treated fabric it is passed through an aqueous solution containing precondensate of tetrakis (hydroxymethyl) phosphonium chloride. The thus treated fabric is dried to reduce its moisture content to about 10 percent by weight of the original dry weight of the fabric and placed in an atmosphere of ammonia gas for 10 minutes and subsequently oxidized, soaped and dried.

2 Claims, No Drawings RENDERING A CELLULOSE-POLYESTER FABRIC FLAME RETARDANT This invention relates to rendering flame retardant a fabric composed of cotton fiber and polyester fibers.

A durable flame retardant finish for cotton/polyester fabrics has been one of the most difficult problems to solve in the field of textile flame retardants. It has been found that flame retardants suitable for cellulosic fabrics are generally not suitable for use on other fabrics, such as polyester fabrics or fabrics which are composed of blends in certain ratios of cellulose and polyester. It is known that cellulose can be made durably flame retardant with products based on the compound, tetrakis (hydroxy methyl) phosphonium chloride while polyester fabrics can be flame retarded durably through thermosoling with bromine containing products, such as tris, 2, 3, dibromopropylphosphate. A blend of the two types of fabrics may be treated by first treating with trisdibromopropylphosphate and then overtreating with tetrakis (hydroxymethyl) phosphonium chloride.

I have found a most advantageous procedure for treating cotton/polyester blends is to apply the flame retardant to the polyester from a dye bath in the presence of a carrier used for dyeing the polyester with or without a dye in the bath. By this procedure the polyester flame retardant is exhausted from the solution.

The treated fabric is dried and then thermosoled. After therrnosoling the fabric is passed through a solution of Proban 210 (precondensate of urea and tetrakis (hydroxymethyl) phosphonium chloride. Sodium acetate is added to the solution as a buffering medium. The treatment is reduced by passing through squeeze rolls to about 80% of the dry weight of the fabric. The fabric is then partially dried in an oven until the residual moisture content is approximately 10% of the original weight of the fabric. The fabric is'then exposed to ammonia gas fumes for approximately 10 minutes. After the ammonia gas treatment the fabric is washed in a neutral soap, hydrogen peroxide oxidizing solution. The fabric is then dried. A softening bath consisting of 0.5% of a polyethylene emulsion may be given to the treated fabric to improve the hand.

The following example is an illustration of the treatment.

EXAMPLE I l. Dye polyester fire retardant treating bath 50 grams polyester/cotton 50/50 blend 4.3 grams Ventrol CKB (chlorinated aromatic carrier) 6.5 grams Pyrotard T-W (50% solution of tris, 2, 3,

dibromopropylphosphate emulsified with amphoteric type surfactant) 50 grams 1.0 solution dye Blue BCN (duPont Co.) C.

I. Disperse Blue 27. 1400 ml of water The temperature of the dye bath, with the fabric present is raised to 180F., at which time 28 ml. 5% acetic acid is added to the bath. The fabric is dyed with agitation at the boil for one hour. The fabric is then removed from the dye bath passed through squeeze rolls and dried.

2. The fabric is then thermosoled at a temperature of 415F for 30 seconds.

3. The following solution is then prepared:

grams Proban 210 (precondensate of tetrakis (hydroxymethyl) phosphonium chloride 9 grams hydrated sodium acetate 90 grams water The fabric is passed through the solution and squeezed to a wet pickup of approximately 70% of the original weight of the fabric. The fabric is then dried at 200F. until the moisture content is about 10% of the original weight of the fabric. The fabric is then placed in an atmosphere containing ammonia gas for 10 minutes.

4. The fabric after the gas treatment is placed in an oxidizing solution containing 0.2% H 0 and 0.5% neutral soap.

5. After oxidation the fabric is dried.

The fabric when tested in accordance with Method 34-1969 American Association of Textile Chemists and Colorists was self extinguishing. The treatment was durable and did not burn after 5 machine launderings with a phosphate containing detergent, such as AATCC Standard Detergent.

I claim:

1. The method of rendering a cotton-polyester fabric flame retardant which comprises first impregnating the fabric with an aqueous liquor comprising water, a'carrier normally used for dyeing polyester fabrics, an emulsified aqueous liquor of tris, 2, 3, dibromopropylphosphate, raising the temperature of the liquor to about 180F. while acidifying it with acetic acid, drying the fabric and thermosoling it for 30 seconds at a temperature of about 415F., thereafter passing the treated fabric through an aqueous solution containing precondensate of tetrakis (hydroxymethyl phosphonium chloride and sodium acetate), removing water from the fabric to reduce its moisture content to about 10 percent by'weight of the original weight of the dry fabric, placing the thus treated fabric in an atmoshphere of ammonia gas for about 10 minutes and then in an aqueous solution of hydrogen peroxide and a neutral soap, and finally drying the fabric.

2. In a method for rendering a cotton-polyester fabric flame retardant wherein the fabric is treated with tris, 2, 3, dibromopropylphosphate and then is overtreated with tetrakis(hydroxymethyl)phosphonium chloride, the improvement which comprises first impregnating the fabric with an aqueous liquor comprising a carrier normally used for dyeing polyester fabrics and an emulsified aqueous liquor of tris, 2, 3, dibromopropylphosphate, drying the fabric, and thermosoling it for about 30 seconds at a temperature of about 415F. 

1. THE METHOD OF RENDERING A COTTON-POLYESTER FABRIC FLAME RETARDANT WHICH COMPRISES FIRST IMPREGNATING THE FABRIC WITH AN AQUEOUS LIQUOR COMPRISING WATER, A CARRIER NORMALLY USED FOR DYEING POLYESTER FABRICS, AN EMULSIFIED AQUEOUS LIQUOR TRIS, 2,3, DIBROMOPROPYLPHOSPHATE, RAISING THE TEMPERATURE OF THE LIQOUR TO ABOUT 180*F. WHILE ACIDIFYING IT WITH ACETIC ACID, DRYING THE FABRIC AND THERMOSOLING IT FOR 30 SECONDS AT A TEMPERATURE OF ABOUT 415*F., THEREAFTER PASSING THE TREATED FABRIC THROUGH AN AQUEOUS SOLUTION CONTAINING PRECONDENSATE OF TETRAKIS (HYDROMETHYL PHOSPHONIUM CHLORIDE AND SODIUM ACETATE), REMOVING WATER FROM THE FABRIC TO REDUCE ITS MOSITURE CONTENT TO ABOUT 10 PERCENT BY WEIGHT OF THE ORIGINAL WEIGHT OF THE DRY FABRIC, PLACING THE THUS TREATED FABRICS IN AN ATMOSPHERE OF AMMONIA GAS FOR ABOUT 10 MINUTES AND THEN IN AN AQUEOUS SOLUTION OF HYDROGEN PEROXIDE AND A NEUTRAL SOAP, AND FINALLY DRYING THE FABRIC.
 2. In a method for rendering a cotton-polyester fabric flame retardant wherein the fabric is treated with tris, 2, 3, dibromopropylphosphate and then is overtreated with tetrakis(hydroxymethyl)phosphonium chloride, the improvement which comprises first impregnating the fabric with an aqueous liquor comprising a carrier normally used for dyeing polyester fabrics and an emulsified aqueous liquor of tris, 2, 3, dibromopropylphosphate, drying the fabric, and thermosoling it for about 30 seconds at a temperature of about 415*F. 